In recent years, energy, particularly its cost, has become a predominant concern of our society. The U.S. government has even established a Department of Energy for the purpose of assisting individuals and corporations in the investigation of more efficient and less expensive forms of energy, means for producing energy and utilization of energy.
In the private sector, electric utility companies have been investigating ways to cut down on distribution losses of electric energy and thereby improve the efficiency of their existing electric distribution systems. One significant area of electricity losses is the increasing theft of electric power by certain consumers which increases the cost of electricity to all consumers.
Accordingly, for some time, electric utilities have been looking for ways to detect and stop the theft of power so that the cost of electric power to all consumers can be reduced.
Typically, the theft of power is effected by a consumer inserting a low resistance jumper cable around the meter so that the current coming into the meter is divided partially through the line conductor passing through the meter and partially through the jumper around the meter. The lower the resistance of the jumper, the greater the diversion of current around the meter and the greater the theft of power.
The method and apparatus of the present invention are useful in detecting this type of power theft where a jumper splits the current around the meter so that only part of the current used by the consumer flows through the meter and the other part flows through the jumper.
As will be explained in greater detail hereinafter, if there is no current passing through the line conductor, the power theft detection circuit of the present invention cannot be utilized to measure a power theft. However, when there is a split of current, part flowing through the line conductor through the meter, and part through the jumper, the power theft detection circuit of the present invention can sense the theft and raise an alarm.
Heretofore, such power theft obtained by splitting the current at the meter and bypassing some of the current used by the consumer through a jumper around the meter was only detected by visual observation or inspection of the consumer's electrical service and meter system or by noting a decrease in the use of electricity by the consumer.
As will be described in greater detail hereinafter, the power theft detection circuit of the present invention and method for using same enable an electric utility to determine whenever a power theft condition exists by reason of a low resistance jumper around the meter.
Additionally, the power theft detection circuit of the present invention can be coupled to a microprocessor such as is found in an electronic or solid state watthour meter of the type disclosed in copending applications Ser. No. 303,599 filed on Sept. 18, 1981 for: SOLID STATE WATTHOUR METER (now U.S. Pat. No. 4,466,074) and Ser. No. 353,476 filed on Mar. 1, 1982 for: ELECTRO-OPTICAL SENSOR FOR WATTHOUR METER (now U.S. Pat. No. 4,489,384), the disclosures of which are incorporated herein by reference.